Passive locking cam &amp; groove coupling

ABSTRACT

A passive locking Cam &amp; Groove female coupling, consisting of a locking latch mounted straddling the exterior of each cam arm attached to the coupling. The latch interlocks with a stop on the coupling body to provide a passive lock when the arm is closed. To open the cam arm, an intentional movement is applied to the latch so that the latch will pivot back and clear the stop thus allowing the cam arm to open.

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] Provisional Patent Application No. 60/204,556. Filed May 16, 2000.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

[0002] Not Applicable

REFERENCE TO A MICROFICHE APPENDIX

[0003] Not Applicable

BACKGROUND OF THE INVENTION

[0004] This invention relates to the general field of quick disconnect couplings known as Cam & Groove couplings for hose and pipe. Cam & Groove couplings have been in common use for many years as quick disconnect coupling joints for hose and pipe involved in fluid transfer. Cam & Groove couplings consist of a male and a female type coupling. Both male and female couplings are tubular in nature and attach to the ends of hose or pipe for the purpose of connecting and disconnecting the lengths of hose or pipe. Together the two couplings comprise a quick disconnect coupling joint.

[0005] The male coupling is constructed with a radial groove around its exterior perimeter. The female coupling is constructed with an interior diameter large enough to accept the insertion of the male coupling into the female coupling's interior. An integral aspect of the female coupling is pivoting cam arms mounted onto the female coupling.

[0006] The cam arms are located between two lugs, known as ears. There are two sets of ears on each female coupling; each set is on opposite sides of the coupling body, 180° apart. Each set of ears contains one cam arm assembly. The cam arms pivot on a steel pin between the ears and retain the male coupling inside the female coupling when the cam arms are in the closed position.

[0007] Since the integrity of the coupling joint is dependent upon the movement of the cam arms, considerable effort has been employed to devise methods of retaining the cam arms in a closed position to prevent unintentional opening and allowing the coupling joint to become uncoupled. Wire safety clips are used for this purpose and are standard on all major brand couplings. The wire safety clips are inserted by the operator through holes in the female coupling in such a manner so that the wire clip is positioned on the outside of the cam arms where they become an obstruction to the opening arc of the cam arm and prevent the cam arm from opening. This method of retaining the cam arm in the closed position is an active action, requiring the operator to perform the additional task of inserting the clips. A passive method of cam arm retention is preferred, which does not require the operator to take any additional action to ensure that the cam arms can not be unintentionally opened.

[0008] U.S. Pat. Nos. 6,015,168 and 5,435,604 and 5,295,717 address the issue of passive cam arm retention in Cam & Groove couplings. These inventions utilize a locking member housed by various methods, inside the cam arm. The locking member in the cam arm interacts with a mating member on the female coupling to accomplish the task of locking the cam arms in the closed position. The locking member located inside the cam arm is attached to the cam arm finger ring. The finger ring is used to release the lock so that the cam arm can be opened. While these inventions work effectively, they have a number of shortcomings.

[0009] The most significant shortcoming is that the releasing of the locking mechanism and the opening of the cam arm are both accomplished by a pulling force applied to the finger ring. The same pulling force applied to the finger ring releases the locking mechanism and opens the cam arm. This arrangement can lead to accidental openings of the cam arm. Cam & Groove couplings are widely used in industrial applications with a large percentage of use as hose quick disconnects. The hose assemblies are subject to severe conditions from handling, moving, dropping and otherwise hard service. In situations where hose assemblies are used on the ground, an object can snag the finger ring and hold it firm while the hose assembly is moved thus releasing the locking mechanism and possibly opening the cam arm.

[0010] Another shortcoming of the fore mentioned inventions is the dependence on the cam arm finger ring to perform the task of releasing the locking mechanism. The cam arm finger ring is subject to possible impairment, due to the harsh environments to which this type of coupling may be subjected. The finger ring can become damaged, lost or removed, making it difficult to release the locking mechanism.

[0011] Still another shortcoming of the fore mentioned inventions is that they have a mating member on the female coupling that the locking mechanism inside the cam arm engages with to retain the cam arm in the closed position. This mating member is cast as an integral part of the female coupling and extends out from the body to protrude into the space normally occupied by a standard cam arm handle. While this arrangement is satisfactory when the specialized locking cam arm designed for that particular brand coupling is used, it is not functional with a standard generic cam arm. The protruding mating member on the female coupling will obstruct and block the rotation needed to complete the closing cycle of a standard generic type cam arm. Should the specifically designed locking cam arm become damaged, jammed or otherwise nonfunctional, a replacement cam arm of the same specialized design must be obtained to restore the coupling to service. Therefore, a standard generic cam arm readily available from numerous sources, will not return the hose assembly to temporary use until a suitable replacement cam arm can be obtained from a specific manufacturer.

SUMMARY OF THE INVENTION

[0012] It is the object of this invention to provide a passive locking mechanism for the cam arms on a Cam & Groove coupling without utilizing the finger ring as an integral aspect of operation.

[0013] It is another object of this invention to provide a passive locking mechanism for the cam arms on a Cam & Groove coupling that would allow for the removal of said locking mechanism and the substitution of a standard generic cam arm assembly, in the case of emergency field repair.

[0014] The present invention is a female Cam & Groove coupling with self locking cam arm assemblies. Each cam arm assembly contains a pivotal locking latch mounted onto the exterior of the cam arm. During the closing cycle of the cam arm, the latch interlocks with the female coupling body in such a manner as to prevent the unintentional opening of the cam arm. The locking latch is self-locking on the closing cycle of the cam arm and manually released by an intentional and secondary action applied by the operator on the opening cycle of the cam arms.

[0015] An additional feature of this invention is that in the event the locking cam arm assembly becomes damaged beyond functionality, the entire locking cam arm assembly can be completely removed from the coupling body and replaced with a standard generic cam arm assembly. The female coupling will continue to be operational as a standard Cam & Groove coupling without the passive locking features. As there are no obstructing members on the female coupling body to interfere with the operation of a standard generic cam arm assembly, the female coupling can be emergency field repaired and continue to be of service.

[0016] Still another feature of this invention is the optional use of a wire safety clip. Even though the use of a wire safety clip is in common use in today's market as a device for cam arm retention, the combination of a wire safety clip and a passive locking cam arm assembly is not common and further enhances this invention.

BRIEF DESCRIPTION OF THE DRAWINGS

[0017] (FIG. 1 and FIG. 2) depict a Cam & Groove coupling joint in accordance with the invention. The male coupling half, designated by the numeral 1 is inserted into the female coupling half 2. The cam arm is attached to the female coupling by a steel pin 3 mounted through the ear lugs 7 that are cast as integral parts of the female coupling. An extended rectangular appendage of the ear lug is the ear lug stop 9 through which a hole 10 is either drilled or cast. The cam arm 4 contains a slotted hole 11 and also contains a finger ring 8 at its extremity. A roll pin 6 secures the locking latch 5 and a torsion spring 12 to the cam arm 4.

[0018] (FIG. 3) is an expanded view of the cam arm assembly and its component parts. This view depicts the locking latch 5 as mounted onto the exterior of the cam arm 4 and held in place by means of a steel roll pin 6. A torsion spring 12 is inserted on the steel roll pin 6 and is located between the locking latch 5 and the spring brace 13 on the cam arm 4.

[0019] (FIGS. 4, 5 and 6) depict the operation the self locking cam arm assembly containing the saddle-type locking latch 5. The locking latch is shown in three different positions as it pivots past the extended rectangular appendage 9 of the ear lug stop on the female coupling body.

[0020] (FIGS. 7 and 8) depicts a complete Cam & Groove coupling assembly, containing both the male coupling 1 and the female coupling 2. The self locking cam arm assemblies are shown in the closed and locked position. These views also depict the optional use of a wire clip 14 inserted through the coupling body and the cam arm assembly.

[0021] (FIGS. 9, 10 and 11) are prior art drawings of previous patents. Each of these drawings shows the locking mechanism located on the inside of the cam arm assembly, with the locking mechanism attached to the finger ring. Also apparent is a mating member on the female coupling that protrudes into the space occupied by the cam arm assembly.

DETAILED DESCRIPTION OF THE INVENTION

[0022] The present invention pertains to the use of a spring-activated locking apparatus, referred to as the latch, and its operation as a passive locking mechanism for the cam arms of a Cam & Groove coupling. (FIGS. 4, 5 and 6) depict the operation of the latch. As the cam arm 4 is rotated to the closed position, the cam arm 4 travels in an arc around the pin 3. During this rotation, the latch 5 swings in the same arc as the cam arm but will come into contact with the end of the ear lug stop 9 before the cam arm 4 completes its closing cycle. The ear lug stop causes the latch 5 to pivot on the roll pin 6, compressing the torsion spring 12, thus changing the arc of the latch 5, relative to the cam arm 4. After the cam arm has completed its rotation, the latch 5 now has the clearance needed to pivot back to the at-rest position by means of the torsion spring 12. In the at-rest position the latch will be nestled underneath the flat end of the ear lug stop 9, as shown in (FIGS. 6, 7 and 8). With the cam arm 4 in the closed position and the latch 5 in the at-rest position, the cam arm cannot be rotated open because the end of the ear lug stop 9 obstructs the arc path of the latch 5. This obstruction prevents the cam arm from opening. To open the cam arm 4, the latch 5 must be manually pivoted back, thus allowing clearance between the latch 5 and the end of the ear lug stop 9.

[0023] The design of the latch 5 is such that once it is mounted on to the cam arm 4, it can only pivot in one direction, as shown in (FIG. 5). This design feature allows the latch 5, on the closing arc of the cam arm 4, to pivot on its own accord past the obstruction of the ear lug stop 9 and not to voluntarily pivot during the opening arc of the cam arm 4. The fact that the latch 5 pivots on the closing arc and is rigid on the opening arc of the cam arm 4 enables it to perform the act of locking the cam arm 4 in the closed position. Once the latch 4 is manually pivoted back, the obstruction is cleared and the cam arm 4 can freely open.

[0024] The optional use of a wire safety clip is shown in (FIG. 7 and FIG. 8). With the cam arm in the closed position, a wire clip 14 can be inserted into the hole 10 on the ear lug stop 9 and through the slotted hole 11 in the cam arm, as shown in (FIG. 1). 

This invention claims a mechanical means of passive retention for the cam arms of a Cam & Groove coupling in the closed position until purposefully opened comprising of:
 1. A Cam & Groove female coupling with extended rectangular lugs located on either side of the coupling body cam arm openings, each lug containing a flat surface at its extremity and located in such a place as to be aligned with a mating flat surface on the cam arm locking latch during the opening and closing cycle of the cam arm.
 2. A Cam & Groove cam arm assembly containing a pivotal locking latch straddling the exterior of the cam arm, in such a manner as the flat surfaces on the end of the locking latch converges with mating flat surface members on the coupling body during the opening and closing cycle of the cam arm.
 3. Retention of the cam arm is a result of the locking latch's ability to pivot on the cam arm, allowing the locking latch to have a variable radial arc during the closing cycle of the cam arm versus a fixed radial arc during the opening cycle of the cam arm: a. during the closing cycle of the cam arm, the ends of the locking latch strike the extended lugs on the female coupling body, further closing motion applied to the cam arm forces the locking latch to pivot against the extended lugs on the female body, in opposition to resistance from a torsion spring mounted inside the locking latch, the locking latch has clearance to pivot in this direction only, allowing the cam arm to move past the extended lugs on the female coupling body until the locking latch has sufficient clearance to pivot back to the at-rest position, at the end of the closing cycle of the cam arm the latch is nestled beneath the extended lugs on the coupling body and can not be unintentionally opened; b. in the closed position of the cam arm, the ends of the locking latch are nestled beneath the extended lugs on the coupling body, when the cam arm begins the opening cycle the extended lugs on the female coupling body are an obstruction in the path of motion of the locking latch thereby restricting the range of motion of both the latch and its cam arm host, to open the cam arm, the latch must be manually rotated back, against the resistance from a torsion spring thus allowing clearance between the ends of the locking latch and the extended lugs on the female coupling, once the latch is pivoted back, the cam arm can freely open. 